Tool for making light metal caps



May 5, 1959 J. E. JONSSON 2,884,886

, TOOL FOR MAKING LIGHT METAL CAPS Filed June 28, 1954 2 Sheets-Sheet 1//V Vf/V TOR;

Arryk y 1959 E. JONSSON 2,884,886

' TOOL FOR MAKING LIGHT METAL CAPS Filed June 28, 1954 2 Sheets-Sheet 2T FIG.6

United States Patent 2,884,886 TOOL FOR MAKINGLIGHT METAL'CAPS JosefEina'r Jonsson, Linkoping, Sweden, assignor to Aktiebolaget'WicandersKorkfabriker, Eskilstuna, Sweden Application June-28,1954, Serial No.439,851 Claims priority, application Sweden June 29, 1953 3 Claims. (Cl.113-42) I The present invention relates to a blanking and forming die'for producing alight metal bottle or similar cap provided with a tearingtab or tongue for tearing oil the cap, the lower edge of the cap beingturned back or curled upwardly except for the above-mentioned tab, whichremains flat. Otherwise the cap does not differ from a usual cap with atearing tab and is applied on the bottle in the usual way by pressingthe side of the cap against the edge of the bottle. By the folding orcurling of its lower edge the cap is attached more securely to the upperedge of the upper annular surface of the groove of the bottle neck. Dueto the fact that the tongue or tearing tab remains fiat, the tearing-offof the cap is made possible exactly as in the case of conventional caps.With this novel cap a higher and more lasting sealing pressure isobtained, so that it can resist high pressure in the bottle, such as isgenerated during the pasteurization of beer and with bottles containinghighly carbonated beverages, and in case too much liquid is filled intothe bottle.

The cap is produced by a combined blanking and forming tool whichcooperates with a supporting ring, and the tool cuts out the blank andforms or draws the cap by a single stroke of the movable parts of thetool, the tool being so arranged that the edge portion of the circularbodyof the cap all round the cap except the tearing tab is turned backby being bent against the curling ring and by being subjected to anevenly distributed pressure, between two surfaces extending from oneside of the tongue to the opposite side of the tongue around the centralaxis of the tool. in a preferred embodiment of the invention a combinedpunching and forming tool is used, having a sleeve-shaped punch, a die,a stamp in the punch, a curling ring which slidably surrounds aresiliently mounted male forming tool. The resilient mounting of themale forming tool permits it to be moved downwardly independently of thecurling ring by the stamp member after the forming of the cap body hasbeen completed and the punch member may then be drawn upwardlyindependently of the stamp member so that the curling edge of the ringmember completes the formation of the curled edge around the previouslyformed body portion of the cap. The punch member is provided with alaterally extending projection which blanks out the tearing tab portionof the cap. This lateral projection of the punch member and the curlingring have flat cooperating surfaces which grip the tearing tab portionof the cap while the body portion is being formed over the male formingtool member. In this connection, it is a feature of the invention thatthe stamp and the male forming tool are not only resiliently movablewith respect to the punch, but are also movable in the same direction asthe punch, after the cap forming motion of the latter has been completedfor curling back the lower edge of the cap.

Referring to the accompanying drawing which forms a part of thisspecification:

Figure l is a perspective view showing a cap produced by the blankingand forming tool.

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Figure 2 is an enlarged'plan view of a blank cut by the tool and fromwhich the cap of Fig. 1 is formed.

Figure 3 is an elevational view, partly in section, showing the blankingand forming tool together with portions of a press in which the tool ismounted.

Figure 4 is an enlarged fragmentary view showing a portion of the loweredge of the cap at an early stage of the curling operation.

Figure 5 is an enlarged fragmentary view similar to Fig. 4 showing alater stage of the curling operation.

Figure 6 is an elevational view similar to Fig. 3 showing the tool afterthe curling operationvhas been completed.

The finished cap differs from conventional caps of the same type only inits upwardly curled or turned back edge forming the strengthened rimportion 1 (Fig. 1) which enhances the security of closure of a bottle orother container by the cap While freely permitting the cap to be tornoff from the container by means of the tab or tongue. The tool, which ismounted in a suitable press, consists of two main parts, one locatedbeneath the strip of blank stock 2 from which the blanks are cut out,the other one being located in its initial position above the strip ofblank stock 2. The lower part is mounted in the press table 3. The upperpart is mounted in a vertically reciprocating head 3a, which can bemoved up and down in a .guideway 4 forming a part of the press frame,otherwise not shown.

The vertical reciprocatory motion of the head 3a is imparted by aconnecting rod 5 and an eccentric 6, the latter being mounted on thedrive shaft 7 of the press. The connection between the head 3a and thecrankshaft comprises a ball and socket joint 8. The above-describedpress construction is well known, and therefore a more detaileddescription is not required.

The punching and forming tool consists of the following elements: asleeve-shaped blanking and drawing punch 10 having a lateral extension10a, a die 11 cooperating with the punch member 10 for punching theblank shown in Fig. 2, the lateral extension 10a of punch member 10operating to punch the tearing tab portion of the blank, the die 11being attached to a sleeve 12 slidably surrounding the punch 10, a stamp14 movable with-- in the punch, a supporting member 15 fixed in thepress table 3, and a supporting and curling ring 16 which is movable upand down in the fixed supporting member 15, and a male forming tool 18movable up and down through the supporting and curling ring 16. Thesupporting and curling ring 16 is connected by guide pins 17 to a lowerring 19. The guide pins 17 pass freely slidably through the fixedsupporting member 15. The lower ring 19 is yieldingly urged upwardly bya helical compression spring 19a which is held stressed by a nut 19b.The nut 19!) is in threaded engagement with a depending sleeve-shapedextension 13 of the fixed supporting member 15. The punch 10 is fixed ina sleeve 20 which, in turn, is fixed in an annular part 21 of thereciprocating head 3a, that is, between a nut 22 and a shoulder 23. Thedie 11 and the sleeve 12 are vertically slidable in a well-known manneron the punch 10, as shown for example, in. my US. Patent No. 2,662,498,issued on December 15, 1953, but are disposedat a lower position inwhich the lower end of the punch 10 is located above the strip of blankstock 2. In this initial position the punch 10 is clear of the strip ofstock 2 permitting the strip of stock 2 to be advanced. After advance ofthe strip of stock 2, the punch 10 will cut a new cap blank as shown inFig. 2 at the beginning of its next downward stroke. During the downwardstroke of punch 10, the die 11 and sleeve 12 are held against downwardmovement by the fixed supporting member 15 as shown in Figs. 3 and 6.The stamp 14 is movable in the punch 10 and a guide sleeve 24, and ispressed upwardly by a compression spring 25.

As shown in the drawing, the stamp 14 is connected to a verticallyreciprocable shaft 27 which, in turn, is connected by a turnbucklemember 28 and a pivot bolt 30a to the free end of an actuating lever 29.The lever 29 is pivoted to the machine frame by a bolt 30 and isprovided intermediate its ends with a cam follower roller 32 whichcooperates with a cam 34 fixed to the drive shaft 7 for rotationtherewith. The cam 34 revolves in a clockwise direction as indicated bythe arrow (Fig. 3). Additionally, in accordance with the invention themale forming tool 18 is movable in the fixed supporting member 15, sothat it can be depressed against the action of a compression spring 35.

The cap is made in the following way:

The strip of blank stock 2 is fed through the combined tool in a slot 26between the die 11 and annular sleeve 12. It is fed stepwise by suitablestock feeding mechanism (not shown). After each advance of the strip ofblank stock 2, the punch 10 moves through the die 11, whereby a blank iscut out and is carried down toward the supporting ring 16 and themandrel 18 which both have their upper surfaces at the same level beforethe start of the forming operation. The punch continues downwards andthe forming operation begins, and the stamp 14 comes in contact with theblank. The supporting ring yieldingly moves downwardly and the blank isbent over the male forming tool 18 towards the position shown in Fig. 3.The cap now formed is indicated in the figure by a thick line and isdesignated by 37. During this forming operation, the tearing tab portionof the cap is gripped between fiat cooperating surfaces of the lateralextension 10a of the punch member and the flat upper surface of thecurling ring member as shown in Fig. 3. At this stage, the punch member10 has not yet reached the lower limit of its travel. At this time, thelever 29 comes into operation. It is rapidly depressed by a projectionon the cam 34 with the result that the cap 37 held tight between thestamp 14 and the male forming tool 18, is pressed downwardly with itslower circular edge against the supporting. ring 16 which is stopped bythe engagement with the fixed supporting member 15. Fig. 3 shows thefirst stage of the upward curling of the edge. By the action of a sharpedged oblique surface 40 on the supporting ring 16 the lower circularedge of the cap receives the initial guiding necessary for the curlingoperation. Figs. 4 and 5 show two later stages of the curling operation.When the punch begins its upward movement, the supporting ring 16 urgedupwardly by the spring 19a presses the partially curled edge of the capagainst the bevelled internal edge of the punch 10 so that the curlingis completed, as shown in Fig. 6. Then the operation is completed andthe tool elements resume their initial position, that is, the punch andthe stamp return to the starting position above the die 11, so that thestrip of stock 2 can be fed one step further in preparation for the nextblanking and forming operation of the tool.

During the formation of the curled edge 1, the tearing tab or tongueportion of the cap is not curled since it is held below the laterallyprojecting portion 10a of the punch 10 which blanks out the tongueportion of the blank.

The invention is not limited to the embodiment shown and described butcan be varied within the scope of the invention.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a tool for cutting in a single cycle by successively cooperatingdie elements blanks of thin sheet material and forming caps from saidblanks, each of said caps being provided with a tearing tab extendingfrom the rim thereof, a hollow sleeve-shaped punch provided with alateral projection the underside of which corresponds to the dimensionsof the tab, a die, drive means for projecting said punch through saiddie to cut a cap blank from said sheet, a stamp mounted forreciprocation within said hollow punch, a second drive means for saidstamp, a male member adapted to cooperate with the inner edge of saidsleeve-shaped punch for drawing the blank to a cap whose lip is formedwith an outwardly curved terminal edge upon a continued actuation ofsaid punch past said die to its full projected position, a resilientlymounted curling ring member slidably surrounding and moved downwardly bythe male member and adapted to cooperate with the inner edge of thepunch for curling the circumferential curved terminal edge of the capextending from both sides of the tab upon reverse movement of saidsleeve punch drive means, said male member being resiliently movablelongitudinally by said stamp in timed relation to said curling ringwhere by upon retrograde movement of said ring with the stamp and malemember in projected position curving of the curved terminal edge of theblank is effected, said punch having its annular internal edge of theunderside, as viewed in radial cross-section, convexly roundedsubstantially along an arc whereby the terminal edge of the cap isformed, and said curling ring member having a flat upper sidesurrounding the male member and bounded close to it by a slightlyerected and, as viewed in radial cross-section, concavely rounded edgeprovided to cooperate with the rounded terminal edge of the cap wherebysaid terminal edge is curled, said arc having a radius which is amultiple of the height of the said edge of the curling ring member, andmeans for controlling simultaneous movement of the stamp and the malemember independently of the punch and of the curling ring member.

2. A tool according to claim 1, further comprising guide means adaptedto feed said sheet material to said punch in strip stock form.

3. A tool according to claim 1, wherein said means for controllingsimultaneous movement comprises a common drive shaft and a plurality ofreciprocatory actuating members operated by said shaft and connectedseparately to said punch and to said stamp.

References Cited in the file of this patent

